1. Field
The invention is in the field of supports or hangers for exterior pipes on building roofs.
2. State of the Art
It is very common in commercial buildings for there to be various types of pipes which are exposed and run along the top of the roofs of such buildings. These pipes may be connected to air conditioning units mounted on a building roof or to various other service units.
Historically, it was common practice for these pipes to be supported above the roof surface at intervals along their length by placing blocks of wood between the roof surface and the pipes. With temperature changes, the pipes expand and contract and, partly because of the large contact surface area between a block and the pipe, the block moves with the pipe. After a period time, the movement of the block against the roof with the weight of the pipe thereon causes damage to the roof, which usually results in a leak and requires expensive roof repair. Even where the blocks are nailed down to the roof, the nails and the wood usually deteriorate in a relatively short time period so that the blocks break loose. Further, wood blocks are difficult to seal so the roof usually leaks about these nail holes.
Various pipe holders that sit on a roof to support the pipes have now been developed and are in common use. For example, U.S. Pat. Nos. 4,502,653 and 4,513,934 show pipe-supporting devices which have substantially flat bottomed bases with pipe supporting structure rising from the base that substantially equally distributes the weight of the pipe over the bottom of the base and thus over the area of the roof in contact with the base. The pipe supporting structures have a substantially V recess having divergent line contacts for receiving and supporting the pipe above the base. In this manner, the pipe is supported in the V with two contact points. This provides for easy sliding movement of the pipe within the support as the pipe expands or contracts. The support of the ""653 patent includes a plastic roller in the bottom of the V recess.
U.S. Pat. Nos. 5,217,191 and 5,685,508 show heavy bases, generally reinforced concrete, which sit on a foot pad glued to a roof surface and support a pipe on a roller adjustably mounted above the base. While the adjustability of the roller is helpful in equalizing the load of the pipe carried by respective supports or hangers, the heavy reinforced concrete bases are difficult to ship and transport.
According to the invention, a pipe hanger or support for use on building roofs includes a molded plastic base with a pair of spaced apart molded stud receiving holes which receive threaded studs the rein which extend upwardly from the base to support a roller on a roller shaft or a pipe supporting strut which extends between such studs. Nuts adjustably support the roller shaft or strut on the studs. The molded base also includes spaced apart receiving recesses for receiving ends of a roller shaft nonadjustably therein to support a pipe roller thereon. Thus, the same base can support a pipe with an adjustable height roller, or a nonadjustable height roller as needed for the particular installation.